Potential of drop-in biofuel production from camel manure by hydrothermal liquefaction and biocrude upgrading: A Qatar case study

Livestock manures significantly contribute to greenhouse gas emissions and soil contamination if not valorised or disposed of properly. Meanwhile, hydrothermal liquefaction has emerged as a promising technology for the conversion of wet wastes into value-added products. As such, this study investigates the potential of hydrothermal liquefaction of camel manure and subsequent upgrading into drop-in fuels in Qatar. Experimental characterisation of manure samples is conducted, while a small-scale plant is simulated and evaluated using Aspen Plus®. Excess treated wastewater of Qatar is utilised as an alternative to fresh water in the process, while power is completely generated on-site. The demonstrated results are promising; whereby, a biocrude yield of 37.9% (on dry and ash-free basis) is achieved, while the biocrude is upgraded into a high-quality bio-gasoline. The produced bio-gasoline contributes to a 7% reduction in greenhouse gas emissions relative to conventional gasoline. The project capital investment is estimated to be 38 M$, while the bio-gasoline's minimum selling price is at 0.87 $/kg, which is still above the market price of conventional gasoline in Qatar (∼0.6 $/kg). However, the conducted sensitivity analysis indicates that scaling-up the plant by 5-fold can shift the fuel's minimum selling price below the average market price. As such, it has a high potential to be locally commercialised especially at times of petroleum price hikes.